Aircon cannot turn on: what to check before approving major replacement

When an aircon does not turn on, the fault can come from power, control, or protection triggers. It does not always mean compressor failure. Start with basic checks, then confirm what was tested before paying for major work.

Primary question

My aircon cannot turn on at all. What should be checked first?

What this pattern can indicate

No-start symptoms can look similar while the root causes are different. Timing and behavior help narrow the path.

  • No response at all: check controller battery, power supply, and breaker status first
  • Beep but no startup: check mode setting, lock states, and indoor control response
  • Starts then cuts off instantly: check protection triggers and startup components
  • Only one unit fails in multi-split setup: check zone-specific wiring or control path

What to check before approving major work

Ask for simple proof of what was tested before you approve expensive replacements.

  • Confirm supply voltage was checked at the unit
  • Confirm remote, receiver, and indoor board response were checked
  • Confirm startup components were tested before compressor-level conclusions
  • Ask what was ruled out and what the next step is

When to get urgent help

Get urgent help if breaker trips repeatedly, there is burning smell, or restart attempts are unstable.

If a major replacement is proposed immediately without basic checks, pause and ask for a second opinion.

Need help with your own unit?

Tell us what is happening. We will assess first, advise one clear next step, and you decide.

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